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Leases - Operating Leases - Additional Information (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2018
USD ($)
shopping_center
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Operating Leased Assets [Line Items]      
Number of shopping centers with land leases | shopping_center 6    
Ground lease expense $ 1.7 $ 1.4 $ 1.2
Rent expense capitalized 0.0 0.1 0.6
Rent expense $ 1.0 $ 1.0 $ 1.0
Minimum      
Operating Leased Assets [Line Items]      
Operating lease term 1 month    
Maximum      
Operating Leased Assets [Line Items]      
Operating lease term 60 years    
Period of lease term 22 years